KR20120104331A - Method and system for routing data to a mobile node in a foreign network - Google Patents

Abstract

A method is disclosed for delivering at least one data packet from a corresponding node in a corresponding network to a mobile node having a home network and connected to a different external network than the home network, wherein the mobile node is a long term IP belonging to the home network. The secondary address is the address of an external network access router of an external network, the networks each being connected to an IP network including at least one data storage device by a home network access router, a corresponding network access router, and the external network access router. Connected, the method is: a. Blocking the at least one data packet and detecting its destination IP address; b. Referencing the at least one data storage device, wherein the auxiliary address of the mobile node is retrieved by using the destination IP address of the at least one packet; And c. Forwarding the at least one data packet directly to the sub-address, and displaying the long term IP address to the external network access router.

Description

METHOD AND SYSTEM FOR ROUTING DATA TO A MOBILE NODE IN A FOREIGN NETWORK}

The present invention relates to network routing, and more particularly, to a system and method for managing connectivity to a mobile node entering a foreign network that is different from the mobile network's home network.

Mobile Internet Protocol (IP) may allow a mobile node to move freely from one point of connection to another in different networks visited along its route. More specifically, the mobile IP protocol describes the operations that allow a mobile node to maintain connectivity during handover from one access router to another.

Mobile IP is described in specifications that may be found from the Internet Engineering Task Force (IETF) and the like, for example, as in Request For Comments (RFC) 3344 and RFC 3776. Mobile IP allows the mobile node to be identified by its home address, regardless of the current point of connection to the Internet. When the mobile node is away from the home network, it is also associated with a care-of-address, which provides information about the current location of the mobile node. Typically, during handover between access routers, the sub-address changes but the home address remains the same.

The following provides an overview of the operation of the latest Mobile IP protocol:

Mobility agents (ie external agents and home agents) announce their presence via agent advertisement messages. The mobile node may optionally request an agent advertisement message from any locally connected mobility agents via an agent request message.

The mobile node receives these agent advertisements and determines whether it is on its home network or on an external network.

When the mobile node detects that it is located on its home network, it operates without mobility services. When returning to its home network from being registered elsewhere, the mobile node deregisters with its home agent, through the exchange of a registration request and registration response message with it.

When the mobile node detects that it is moving to an external network, it obtains a secondary address for the foreign network.

The mobile node operating away from home then registers its new sub-address with its home agent, possibly via an external agent, through the exchange of registration requests and registration response messages with it.

Datagrams sent to the home address of the mobile node are interrupted by its home agent, tunneled by the home agent to the sub-address of the mobile node, received at the tunnel endpoint, and finally the mobile Is passed to the node.

In the reverse direction, datagrams sent by the mobile node are generally delivered to their destination using standard IP routing mechanisms, not necessarily passing through the home agent.

When away from home, Mobile IP uses protocol tunneling to hide the mobile node's home address from intermediate routers between its home network and its current location. The tunnel ends at the secondary address of the mobile node. The secondary address should be an address to which datagrams can be delivered via conventional IP routing. At the secondary address, the original datagram is removed from the tunnel and forwarded to the mobile node.

The problem with modern approaches is that so-called triangular routing is not an efficient data transfer, as all traffic from the external network to the mobile node is routed through the home agent in the mobile node's home network. The use of long term IP addresses belonging to the mobile network's home network makes this technique necessary.

Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise.

The term "router" refers to a dedicated network element that receives packets and forwards them towards a destination. In particular, routers are used to extend or divide networks by forwarding packets from one subnet to another. Routers typically operate on Layer 3 TCP / IP of the Open Systems Interconnection (OSI) reference model for networking. However, some routers may provide additional functionality that operates above Layer 3 of TCP / IP in the OSI reference model.

The term "access router" refers to a router associated with a mobile node for providing IP connectivity between the mobile node and other nodes on an IP network, such as a correspondent node. The access router is a dedicated network element coupled to the IP network, but it can also communicate with one or more points of connection for the wireless network.

The term "mobile node" refers to a device (eg, wireless) that changes the point of connection from one network or sub-network to another. The mobile node can change its location without loss of connectivity and without changing its IP address; It can continue to communicate with other Internet nodes at any location using its (constant or long term) IP address, assuming link-layer connectivity to the access point is available. The mobile node is provided with a long term home IP address on the home network. This home address is managed in substantially the same way that a "permanent" IP address is provided to a fixed host. A mobile node can change its access point from one link to another, while still reaching through its home address.

The term "link-layer", also referred to as a data-link layer or network interface layer, refers to a device driver in an operating system and a corresponding network interface card configured to enable physical interfacing to network media such as cables, wireless media, and the like. . The link-layer typically operates at Layer 2 of the Open Systems Interconnection (OSI) reference model for networking.

The term "IP connectivity" refers to the ability to send and receive conventional IP packets.

The term "flow" refers to the flow of packets.

The term “secondary address” refers to the end point of the tunnel towards the mobile node for datagrams forwarded to the mobile node while it is away from home.

The term "communicator node" refers to the peer with which the mobile node communicates. The source node may be mobile or stationary.

The term "external network" refers to any network other than the home network of the mobile node.

The term "home address" refers to an IP address assigned to a mobile node for an extended period of time. It remains unchanged no matter where the node is connected to the internet.

The term “home network” refers to a network, possibly virtual, with a network prefix that matches that of the mobile node's home address. Note that standard IP routing mechanisms will deliver diagrams destined for the mobile node's home address to the mobile node's home network.

The term "link" refers to a facility or medium through which nodes can communicate at the link layer. Links form the basis of the network layer.

The term "link-layer address" refers to an address used to identify an endpoint of some communications over a physical link. Typically, the link-layer address is the media access control (MAC) address of the interface.

The term "mobility agent" refers to a home agent or an external agent.

The term "node" refers to a host or a router.

The term "tunnel" refers to a path preceding a datagram while it is encapsulated. The model is that while a datagram is encapsulated, the datagram is routed to a well-known decapsulation agent that decapsulates the datagram and then delivers it exactly to its ultimate destination.

The term “landing network” refers to a network other than the home network of a mobile node, which is currently connected to the mobile node.

The term “agent discovery” refers to home agents and foreign agents that announce its availability on each link they provide a service. The newly arrived mobile node may send a request on the link to see if there are any promising agents.

The term "registration" indicates that when the mobile node is away from home, it registers its secondary address with its home agent. Depending on its connection method, the mobile node will register directly with its home agent or through an external agent forwarding registration to the home agent.

It is an object of the present invention to provide methods and systems that eliminate the need for triangular routing in mobile IP.

According to a first aspect of the present invention, a method for delivering at least one packet originating from a corresponding node in a corresponding network to a mobile node having a home network and connected to a different external network than the home network is disclosed. The mobile node has a long term IP address belonging to the home network and an auxiliary address which is an address of an external network access router of the external network, wherein the home network, the corresponding network and the external network include at least one data storage device; The method is coupled to each other by an IP network, and wherein the networks are each connected to the IP network by a home network access router, a corresponding network access router, and the external network access router, by the corresponding network access router:

a. Blocking the at least one data packet and detecting its destination IP address;

b. Referencing the at least one data storage device, whereby the supplemental address of the mobile node is retrieved by using the destination IP address of the at least one packet; And

c. Forwarding the at least one data packet directly to the secondary address, and also allowing the external network access router to forward the at least one data packet to the mobile node of the mobile node to the external network access router. And displaying the long term IP address.

According to embodiments of the present invention, the method is executed on a data packet basis.

According to embodiments of the present invention, the method further comprises receiving notifications of changes in the secondary address of the mobile node such that referencing the data storage is not necessary on a packet basis.

According to embodiments of the present invention, the data storage device includes a DNS server.

According to embodiments of the present invention, forwarding the at least one data packet by the corresponding network access router directly to the secondary address is based on layer 3 connectivity of the ISO reference model.

According to embodiments of the present invention, the method includes tunneling the at least one data packet between the corresponding network access router and the external network access router.

According to embodiments of the present invention, the long term IP address is a public address.

According to a second aspect of the invention, a method is disclosed for updating internet location information for a mobile node on a storage device by an access router of a network, wherein the storage device is accessible via the internet, the method comprising: Transmitting the secondary address of the mobile node and the long term IP address of the mobile node to the storage device through the IP network.

According to embodiments of the present invention, the access router is a home network access router of the mobile node.

According to embodiments of the present invention, the access router is an external network access router of the mobile node.

According to a third aspect of the present invention, an access router for an IP network is disclosed, which forwards a long term IP address and an auxiliary address of a mobile node belonging to its domain to a DNS server in the IP network to which it provides access. It is composed.

According to a fourth aspect of the present invention, an access router for an IP network is disclosed, which blocks data packets originating from nodes in its domain and directed to nodes outside the domain, and deciding destination addresses of the packets. Extract and retrieve auxiliary addresses corresponding to destination addresses of the packets from storage in the IP network.

Further aspects of the invention are described by the dependent claims. Features from the dependent claims, features of any of the independent claims, and any features of the other dependent claims are deemed appropriate to one skilled in the art, and are also specified as defined by the claims. Can be combined in combinations.

The accompanying drawings are used to illustrate embodiments of the invention.

1 illustrates the manner of a typical network architecture in which the mobile IP mechanism is used.
2 illustrates the latest mobile IP routing mechanisms.
3 illustrates an improved mobile IP routing mechanism in accordance with aspects of the present invention.

Reference numerals are chosen such that they are the same for similar or identical elements in different diagrams or figures.

The above and other advantageous features and objects of the present invention will become more apparent and the present invention will be better understood from the following detailed description when read in conjunction with the respective figures.

The description of aspects of the invention is performed by specific embodiments and with reference to the drawings, although the invention is not so limited. The drawings described are only schematic and should not be considered as limiting. By way of example, certain elements or features may be viewed as not proportional or unbalanced with respect to other elements.

In the description of specific embodiments in accordance with the present invention, the various figures are sometimes grouped together in a single embodiment, figure, or description thereof to facilitate understanding of one or more of the various aspects of the invention. This should not be construed as though all features of the group necessarily exist to solve a particular problem. Aspects of the invention may exist less than all features of a group of such features present in the description of a particular embodiment.

In Fig. 1, the manner of a typical network architecture in which the mobile IP mechanism is used is described. A number of access networks, namely correspondence network (CN), home network (HN), and external network (FN) are interconnected by said Internet network. The terminals are connected by access networks. The terminal typically has layer 2 connectivity, for example, to the layer 3 node, which is an edge router in the access network (called domain) to which the terminal is connected. Each of the networks is connected by a respective access router to the Internet, namely a corresponding network access router (CNAR), a home network access router (HNAR), and an external network access router (FNAR).

In a typical situation, for example, the correspondent node C belonging to the correspondent network domain forwards the packet to the mobile node M. This mobile node M belongs to the home network HN from which it obtains a long term IP address. When the mobile node moves and accesses external networks, the transfer of data packets sent from the corresponding node to the mobile node is based on the long term IP address and auxiliary address of the mobile node. The secondary address may typically be the IP address access router of the external network.

Figure 2 illustrates the mechanism of "triangular routing" as a result of the state-of-the-art mobile IP mechanism. When sending a packet from the corresponding node towards the mobile node, the packet is directed to the long term IP address of the mobile node. The home network access router (HNAR) blocks the packet destined for the mobile node, and the FNAR of the secondary address of the mobile node, which is typically the IP address of the access router (FNAR) of the external network or by the mobile node. It is recognized by. The HNAR then forwards the packet to the FNAR by tunneling it to the mobile node's secondary address. In the FNAR, the tunnel is terminated and there is an association between the long term IP address of the mobile node and the link layer (or layer 2) address of the mobile node, so that the FNAR sends the information to the mobile node M. Allow forwarding. This type of packet routing is not efficient because all traffic from the external network to the mobile network is routed through the home agent in the home network of the mobile node.

In Figure 3, an improved mobile IP routing mechanism is shown in accordance with embodiments of the present invention. The basic architecture required is very similar to the modern architecture, but it further includes a data storage, for example a domain name server (DNS). The use of the proposed DNS server avoids the need for triangular routing of packets between the correspondent node and the mobile node as follows: the correspondent node forwards this packet through the correspondent network and the correspondent network access router (CNAR). When transmitting towards a mobile node, the CNAR looks for storage means (e.g., a DNS server) to intercept the packet and retrieve location data based on the long term IP address of the mobile node. In the DNS, the long term IP address of the mobile node is linked with (or tied to) the secondary address of the mobile node. The supplemental address of the mobile node may be returned to the CNAR, so that the CNAR will forward the packet to an access router of the foreign network corresponding to the supplemental address of the mobile node by tunneling the packet over the Internet. Can be. In the FNAR, the tunnel is terminated and the destination address of the original IP packet is associated with the link layer address of the mobile node in the foreign network. The packet can then be forwarded to the mobile node based on link layer connectivity. This procedure allows to avoid the triangular routing and is therefore more transmission efficient than modern mechanisms. It requires maintenance of data storage, for example DNS, wherein the long term IP address (preferably a public IP address) is stored and linked with the current secondary address of the mobile node.

When the mobile node moves along different external networks, registration of the node with each of these external networks includes obtaining a secondary address in each of these networks. Once the supplemental address is obtained by up-to-date mechanisms, the supplemental address is typically forwarded to the home network access router either directly by the mobile node or indirectly through the external network access router. According to the standardized mobile IP protocol, the external network access router and the home network access router (or external agent and home agent) know the auxiliary address of the mobile node at any time. The update of the DNS may therefore be executed by the home network access router (or home agent), preferably because such party is typically a trusted party. If the external network access router (or external agent) is a trusted party, the maintenance of binding information between the long term IP address and the secondary address of the mobile node in the DNS may be performed by the FNAR (or foreign agent). have.

It can be noted that although the concept of the standard remains the same as described in the mobile IP standards of foreign agent FA and home agent HA, the functions are different.

The foreign agent (FA) knows the location of the mobile node visiting its domain;

The home agent (HA) means that the home agent is a trusted entity preferred for managing the terminal and update information in the DNS for the terminal in its domain. I know the location.

The registration process for the mobile node in external networks may correspond to the latest registration process. The foreign agent and home agent are located on the edge of the layer 2 domain.

For communication from the corresponding node to the mobile node;

If the mobile node is in its home network, all routing takes place via the home agent of the "mobile" node and the packet is forwarded unchanged. This corresponds to normal mobile IP behavior.

If the mobile node is in a visited (or external) network, direct routing is possible, where the packet is tunneled from an access router of the corresponding network to an access router of the external network (or foreign agent). This means that the foreign agent can operate according to the mobile IP V4 specification.

Advantages of embodiments of the present invention are that the mechanism is suitable or technically compatible with the current IP V4 architecture and no changes to the terminals are required. An important advantage is that triangular routing can be avoided and more efficient data transmission can be achieved.

According to embodiments of the present invention, the reference of the DNS is necessary for each of the packets forwarded from the corresponding node to the mobile node since the mobile node may change the access network and thus the secondary address. Can be.

According to preferred embodiments of the present invention, when the DNS server including binding information between the long term IP address of the mobile node and the auxiliary address of the mobile node, a change in the auxiliary address occurs for the mobile node. Each time a new secondary address can be automatically forwarded to the corresponding network access router (and can be adapted for this). Using this mechanism in the DNS server allows the removal of the active reference step of the DNS server by the access router of the corresponding network for all packets. After reference to the second packet of the data stream, this mechanism may also no longer be needed.

While some embodiments described herein include some other features only included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the present invention and are understood by those skilled in the art. Different embodiments are formed as follows.

While the principles of the invention are shown above in connection with specific embodiments, it should be clearly understood that this description is made by way of example only and not as a limitation of the scope of protection as determined by the appended claims.

Claims (12)

A method for delivering at least one data packet originating from a corresponding node in a corresponding network to a mobile node having a home network and connected to a foreign network different from the home network, wherein the mobile node is connected to the home network. Has a long-term IP address to belong to and a care-of-address that is an address of an external network access router of the external network, wherein the home network, the corresponding network, and the external network include at least one data storage device. Wherein the networks are coupled to each other by an IP network, the networks being connected to the IP network by a home network access router, a corresponding network access router, and the external network access router, respectively.
By the corresponding network access router:
a. Blocking the at least one data packet and detecting its destination IP address;
b. Referencing the at least one data storage device, whereby the supplemental address of the mobile node is retrieved by using the destination IP address of the at least one packet; And
c. Forwarding the at least one data packet directly to the secondary address, and also indicating the long term IP address of the mobile node to the external network access router, such that the external network access router forwards the at least one data packet to the mobile node. And executing the step of enabling forwarding to a data packet. The method of claim 1,
A method of delivering data packets, executed on a data packet basis. The method of claim 1,
Receiving notifications of changes in the secondary address of the mobile node, so that referring to the data storage is not necessary on a packet basis. The method according to any one of claims 1 to 3,
The data storage device comprises a DNS server. The method according to any one of claims 1 to 4,
And forwarding the at least one data packet directly to the secondary address by the corresponding network access router is based on layer 3 connectivity of an ISO reference model. The method of claim 5, wherein
Tunneling the at least one data packet between the corresponding network access router and the external network access router. 7. The method according to any one of claims 1 to 6,
And the long term IP address is a public address. A method for updating internet location information for a mobile node in a storage device by an access router of a network, wherein the storage device is accessible via the internet.
Transmitting the mobile node's secondary address and the mobile node's long term IP address to the storage device via the IP network. The method of claim 8,
And the access router is a home network access router of the mobile node. The method of claim 8,
And the access router is an external network access router of the mobile node. In an access router for an IP network,
And forward the long term IP address and secondary address of the mobile node belonging to the domain of the access router to a DNS server in the IP network providing access. In an access router for an IP network,
Block data packets originating from nodes in the domain of the access router and directed to nodes outside the domain of the access router, extracting destination addresses of the packets, and storing the packets of the packets from storage at the IP address. And retrieve an auxiliary address corresponding to the destination addresses.

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